Thesis(M.S.)--Auburn University, 2005. / Abstract. Vita. "References: Curry, J.E., S.H. Crim, O. Güven, J.G. Melville, and S. Santamaria, 2003. "Scour Evaluations of Two Bridge Sites in Alabama with Cohesive Soils," Highway Research Center 930-490R, October 2003, Auburn University, AL Includes bibliographic references.

Thesis (M.S.E)--Youngstown State University, 1998. / Includes bibliographical references (leaves l10-111).

Scour is the process of sediment erosion around bridge piers and abutments due to natural and man-made hydraulic activities. Excessive scour is a critical problem that is typically handled by enforcing design requirements that make the submerged structures more resilient. The purpose of this research is to demonstrate the feasibilities of the Optical- Based Green Laser Scanner and HydroLite Sonar in a laboratory setting to capture the 3D profile of simulated local scour holes. The Green Laser had successfully reconstructed a 3D point-cloud imaging of scour profiles under both dry and clear water conditions. The derived scour topography after applying water refraction correction was compared with the simulated scour hole, and was within 1% of the design dimensions. The elevations at the top and bottom surfaces of the 6.5-inch scour hole were -46.6 and -53.11 inches from the reference line at the origin (0,0,0) of the laser scanner. The HydroLite Sonar recorded hydrographical survey points of the scour’s interior surface. The survey points were then processed using MATLAB to obtain a 3D mesh triangulation. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2018. / FAU Electronic Theses and Dissertations Collection

No description available.

Recent natural disasters, such as major tsunamis, have prompted researchers and practicing engineers to improve their understanding of the impacts of bore-like waves on structures and their foundations. The high velocity and the relatively short duration of hydraulic bores causes local scouring which is different from that generated by river flows and waves. The present study uses an experimental model to simulate the propagation of a hydraulic bore over a movable sediment bed placed around a circular pier-like structure. Measurements of water surface elevation, bore propagation velocity and scour distribution were taken. The linear relationship between reservoir depth and bore depth led to an increase in flow acceleration, and thus to an increase in flow velocity. Final scour bed elevations indicated that scour depth was highly dependent on the bore velocity. The scour depth ratios suggested in current design guidelines were significantly lower than those obtained in this study.

Yes / Local scour around submarine pipelines can affect the stability of the pipeline. The accurate estimation of the scour around submarine pipelines has been a hot topic of research among marine engineers. This paper presents results from a numerical study of clear-water scour depth below a submarine pipeline for a range of the steady flow conditions. The flow field around the pipeline under scour equilibrium condition is numerically simulated by solving the Reynolds-Averaged Navier-Stokes (RANS) equations with the standard k-ε turbulence closure. The flow discharge through the scour hole for various flow conditions is investigated. The results are used to establish the relationship between the flow discharge and the maximum scour depth. Incorporated with the Colebrook-White equation, the bed shear stress is obtained and an iterative method is proposed to predict the scour depth around the submarine pipeline. The calculated scour depths using the present method agree well with the laboratory measurements, with the average absolute relative error being smaller than that using previous methods, indicating that the proposed method can be used to predict the clear-water scour around the submarine pipeline with satisfactory accuracy. / National Nature Science Fund of China (Grant No.50879084, 51279189), the Open Fund from the State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University (SKHL1302),China Scholarship Council, Public Projects of Zhejiang Province (2016C33095) and the Natural Science Fund of Zhejiang Province (LQ16E090004).

Yes / This paper presents the results of laboratory experiments and numerical simulations to investigate the effect of different piggyback pipeline configuration on the morphology of local seabed scour subject to steady currents. Piggyback pipeline configuration investigated includes the commonly used piggyback pipeline, namely a small pipe attached on the top of large pipe and new form of piggyback pipeline proposed in this study in which a small pipe is attached to the large pipe on the upstream and downstream side, respectively. Pressure gradient, drag coefficient, lift coefficient and scour extent around pipelines are measured and analyzed for a range of pipelines and current conditions. Results show that the vortex strength downstream of the commonly used piggyback pipeline is larger than that for a single as well as the new piggyback pipeline under the same condition. This new type piggyback pipeline can effectively reduce the depth and width of the scour hole. In particular, when the ratio of the small pipe diameter over the large pipe diameter is greater than 0.3, little scour under this new type piggyback pipeline occurs for the test conditions. The bed topography downstream of the pipe has also been altered to favor the backfill. / National Natural Science Foundation of China (No. 51279189).

In 1983, Laursen and Flick (1) proposed an equation to predict the depth of scour at the toe of a sloping sill. The equation was developed for use with clear-water only since their experiments did not fully investigate the effect of sediment transport. Their report also left open the question of the possible ramifications of sediment transport on the depth of a scour hole. This thesis is an exploratory investigation of the effect of the sediment transport phenomenon on the depth of a scour hole. It will discuss and compare both the clear-water and sediment transport conditions and to explore if the sediment transport rates to be expected in most streams would have a substantial effect on the scour at the toe of a sloping sill.

A method called SRICOS-EFA is presented in this dissertation for scour prediction. The method is based on the calculation of two basic parameters: the maximum depth of scour and the initial rate of scour. The maximum depth of scour is based on an equation obtained from flume tests and the initial rate is based on an equation giving the initial shear stress obtained from numerical simulations. The initial scour rate is then read on the Erosion Function Apparatus (EFA) erosion function curve at the corresponding value of the calculated shear stress. A hyperbola is used to connect the initial scour rate to the maximum scour depth and describes the complete scour depth vs. time curve. The erodibility function curve can be measured in the EFA. As the results show, the SRICOS-EFA method can handle the multi-flood hydrograph and multilayer soil system. It can be used to solve the complex pier and contraction scour alone; it can also handle the superposition of complex pier scour and contraction scour. A simplified SRICOS-EFA method was developed based on the case histories for contraction scour. EFA tests were performed to investigate the influence of different pH values and different levels of salinity on the soil erodibility. An attempt was made to find the correlation between the critical shear stress, and the initial slope of the erodibility function on the one hand and some geotechnical parameters on the other. A solution for future hydrograph prediction was developed in this dissertation. The prediction consists of using a past hydrograph, preparing the frequency distribution plot for the daily stream flows, sampling the distribution randomly and preparing a future hydrograph, which has the same mean and standard deviation as the measured hydrograph. A frequency distribution plot of scour depths can be used to quote a scour depth with a corresponding probability of occurrence and risk level based on future hydrographs. In the verification process, 10 bridge case histories and 3 scour databases were used to check whether the method is good enough to provide sound results in real cases.

Thesis (Ph.D)--Civil and Environmental Engineering, Georgia Institute of Technology, 2006. / Committe Chair: Terry W. Sturm; Committe Members: Dr. Fotis Sotiropoulos; Committee Members: Dr. Philip J. Roberts; Committee Members: Dr. Donald R. Webster; Committee Members: Dr. Anthony Hayter. Part of the SMARTech Electronic Thesis and Dissertation Collection.